Much of our modern life is spent sitting down, whether in front of a computer or TV, or commuting in our cars. Now, new research shows that the obesity epidemic and rise of type-2 diabetes experienced in developed countries could soon impact low-income countries, as more people are able to own TVs, computers and cars.

The study, led by Prof. Scott Lear of Simon Fraser University in Canada, was published in CMAJ, the journal of the Canadian Medical Association.

In a linked editorial, Kirsten Patrick, deputy editor of CMAJ, notes that increasingly, evidence is suggesting that too much time sitting is linked to ill health and is a risk factor for early death.

However, she adds that the 2008 Physical Activity Guidelines from the US Department of Health and Human Services have not yet been revised to warn against the dangers of sitting for large amounts of time.

Likewise, while the American Heart Association recommends 30 minutes of physical activity, 5 days per week, the organization does not focus on the dangers of consistently sitting at all other points of the day.

To examine how sedentary-inducing technologies - like TVs and cars - affect physical activity, Prof. Lear and his team of international researchers assessed data on over 150,000 adults from 17 countries, which ranged from high-, middle- and low-income.

'Potentially devastating health care consequences'

The researchers surveyed participants about ownership of these devices, as well as activity and diet. They found that among owners of TVs, cars and computers, there was a 400% increase in obesity and a 250% increase in diabetes.

Using cars as a primary mode of transportation increases sedentary time. Individuals who own a TV, car and computer had a 31% decrease in physical activity in the study, compared with those who did not own any of the three.

Additionally, owning all three devices was linked to a 31% decrease in physical activity, a 21% increase in sitting and a 9 cm increase in waist size, compared with individuals who did not own any of the devices.

Interestingly, the team did not find this association in high-income countries, where they suggest the effects of owning such items has already occurred. Indeed, they point out that these high-income countries already have high rates of these effects.

Prof. Lear says their findings could lead to "potentially devastating societal health care consequences" in developing countries, where obesity and diabetes rates are expected to rise.

He adds:

"With increasing uptake of modern-day conveniences - TVs, cars, computers - low- and middle-income countries could see the same obesity and diabetes rates as in high-income countries that are the result of too much sitting, less physical activity and increased consumption of calories."

Kirsten Patrick argues that we should "not wait for proof from a randomized trial to tell us that 'parachutes save lives,'" and advocates that we should "start a loud conversation now about too much sitting and what we need to do about this risk factor for early death."

The association between ownership of common household devices and obesity and diabetes in high, middle and low income countries, Scott A. Lear, et al., CMAJ, doi: 10.1503/cmaj.131090, published online 10 February 2014, Abstract.

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